Data from: Experimental evolution reveals balancing selection underlying coexistence of alternative male reproductive phenotypes

Heritable alternative reproductive phenotypes (ARPs), which differ in traits associated with competition for mates, occur across taxa. If polymorphism in the genes underlying ARPs is maintained by balancing selection, selection should return ARP proportions to their equilibrium if that equilibrium is perturbed. Here, we used an experimental evolution approach to directly test this prediction in male Rhizoglyphus robini, in which two heritable morphs occur: armoured fighters and more female-like, benign scramblers. Using selection lines nearly fixed for male morph, we constructed replicate populations consisting of 50% or 94% fighters, and allowed them to evolve for 14 generations in two types of environment: simple or spatially complex. We found that in both types of populations, the proportion of fighters converged on values within a narrow range of 0.70-0.83, although the rate of convergence was slower in the complex environment. Our results thus demonstrate balancing selection acting on polymorphism(s) underlying ARPs可遗传的替代性生殖表型（alternative reproductive phenotypes, ARPs）的性状与配偶竞争相关，广泛分布于各生物类群中。若维持ARPs的基因多态性由平衡选择所介导，则当该平衡被扰动时，选择应能将ARP的比例恢复至平衡状态。本研究采用实验进化方法，在雄性罗宾根螨（Rhizoglyphus robini）中直接验证该预测。该物种存在两种可遗传形态：具装甲的格斗型个体，以及更类似雌性的温和游移型（scramblers）个体。我们以几乎固定为单一雄性形态的选择系为基础，构建了格斗型个体占比分别为50%和94%的重复种群，并将其分别置于简单环境与空间复杂环境中培养14个世代。结果显示，两类种群中的格斗型个体占比均收敛于0.70~0.83的狭窄区间内，不过复杂环境中的收敛速率更慢。综上，本研究结果证实平衡选择作用于维持ARPs的基因多态性。